tmp <- textConnection( 
"day     A       B 
0       10.0    10.0 
7       9.0     9.1 
14      8.0     8.2 
21      7.0     7.3 
28      6.0     6.4 
35      5.0     5.5 
42      4.0     4.5 
49      3.0     3.6 
56      2.0     2.7") 
x <- read.table(tmp, header=TRUE) 
close.connection(tmp)
head(x)